Intramolecular ene reaction of epoxyallylsilanes: synthesis of allyl- and vinylsilane-functionalized cyclohexanols

Asunción Barbero; Pilar Castreño; Gloria Fernández; Francisco J Pulido

doi:10.1021/jo051868g

Intramolecular ene reaction of epoxyallylsilanes: synthesis of allyl- and vinylsilane-functionalized cyclohexanols

J Org Chem. 2005 Dec 23;70(26):10747-52. doi: 10.1021/jo051868g.

Authors

Asunción Barbero¹, Pilar Castreño, Gloria Fernández, Francisco J Pulido

Affiliation

¹ Departamento de Química Orgánica, Facultad de Ciencias, C/Dr Mergelina s/n, 47011 Valladolid, Spain.

PMID: 16355996
DOI: 10.1021/jo051868g

Abstract

[reaction: see text] Epoxyallylsilanes bearing the bulky tert-butyldiphenylsilyl group undergo an uncommon tandem rearrangement-cyclization process upon treatment with Lewis acids. Two pathways for the carbonyl ene reaction are observed: one leading to allylsilane-cyclohexanols when the epoxyallylsilane (28-31) is nonsubstituted, 2-, or 4-monosubstituted and other leading to vinylsilane-cyclohexanols when the epoxyallylsilane (24-27) is 2,4-disubstituted or trisubstituted. An explanation for the observed regio- and stereoselectivity is advanced and a reliable mechanism proposed.